Derivative Financial Instruments and Hedging Activities - Schedule of Fair Value of Derivative Instruments (Detail) - USD ($) $ in Millions	Feb. 29, 2024	May 31, 2023
Derivative [Line Items]
Asset Derivatives at Fair Value	$ 3.9	$ 2.3
Liability Derivatives at Fair Value	9.1	9.8
Derivatives Designated As Hedging Instruments | Commodity Contracts
Derivative [Line Items]
Asset Derivatives at Fair Value	0.2	0.1
Liability Derivatives at Fair Value	3.7	2.8
Derivatives Designated As Hedging Instruments | Commodity Contracts | Accounts Payable
Derivative [Line Items]
Liability Derivatives at Fair Value	3.7	2.7
Derivatives Designated As Hedging Instruments | Commodity Contracts | Receivables
Derivative [Line Items]
Asset Derivatives at Fair Value	0.2	0.0
Derivatives Designated As Hedging Instruments | Commodity Contracts | Other Assets
Derivative [Line Items]
Asset Derivatives at Fair Value	0.0	0.1
Derivatives Designated As Hedging Instruments | Commodity Contracts | Other Liabilities
Derivative [Line Items]
Liability Derivatives at Fair Value	0.0	0.1
Derivatives Not Designated As Hedging Instruments | Commodity Contracts
Derivative [Line Items]
Asset Derivatives at Fair Value	3.7	2.2
Liability Derivatives at Fair Value	5.4	7.0
Derivatives Not Designated As Hedging Instruments | Commodity Contracts | Accounts Payable
Derivative [Line Items]
Liability Derivatives at Fair Value	5.4	7.0
Derivatives Not Designated As Hedging Instruments | Commodity Contracts | Receivables
Derivative [Line Items]
Asset Derivatives at Fair Value	3.7	2.2
Derivatives Not Designated As Hedging Instruments | Commodity Contracts | Other Assets
Derivative [Line Items]
Asset Derivatives at Fair Value	0.0	0.0
Derivatives Not Designated As Hedging Instruments | Commodity Contracts | Other Liabilities
Derivative [Line Items]
Liability Derivatives at Fair Value	$ 0.0	$ 0.0